<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <!-- 根据公式计算体重，判断是偏重还是偏瘦 -->
    <script>
      var par = prompt('请输入：标准体重（千克）')
      var pent = prompt('请输入：身高（厘米）')
      var par = Number(par * 2)
      var ant = (par = Number(pent) - 105)
      if (ant >= 30) {
        alert('偏瘦')
      } else {
        alert('偏瘦')
      }
    </script>
  </body>
</html>
